1. Field of the Invention
The present invention relates generally to the field of systems for producing minerals such as oil and gas from geological formations via subterranean wells. More particularly, the invention relates to a technique for producing flowable minerals by extracting fluids from one or more wells and depositing the fluids in a gathering or collection well where the fluids may separate and be subsequently pumped to a collection or processing point.
2. Description of the Related Art
A wide range of completion techniques have been devised and are presently in use for producing useful flowable minerals, such as oil and gas, from subterranean deposits. In production wells having sufficient natural pressure to force the fluids to a collection point, typically at the earth's surface, the wells may be exploited directly without artificial pumping means. Where, however, the well pressures are insufficient for this purpose, various types of pumps are employed to raise the fluids to the earth's surface. These pumps may be located at least partially above the earth's surface, with pumping elements or rods extending to the location of the fluid. However, in many applications, it is preferable to use a submersible pumping system deployed in the well and driven electrically to displace the wellbore fluids under sufficient pressure to convey them to the collection or processing point.
In many pumping systems used to extract petroleum and similar products from production wells, the production rate may be hampered by the presence of fluids of lesser interest, or by elevations through which the fluids must be raised. Specifically, in many petroleum wells, liquid phase components of wellbore fluids are mixed or disbursed with gaseous phase components. Separators may be employed to at least partially extract the gaseous phase components for production of the petroleum, or the liquid and gas may be allowed to gravity separate, where the dispersion permits. However, such techniques may not always present the most economical solution from the point of view of actual production rates. Accordingly, wellbore fluids may be raised to the earth's surface and stored in a gathering station, typically an above-ground container, where gas-phase components are allowed to slowly migrate from the liquid-phase components.
While such collection stations are generally effective for separating the wellbore fluid components from one another, they are not without drawbacks. For example, depending upon the well production volume and collection schedules, the collection stations may occupy significant real estate. Also, such collection stations are not generally permitted or desirable in environmentally sensitive areas, near residential areas, and so forth.
In addition to problems associated with separation of wellbore fluid components, production from groups of wells having mixed gas and liquid components is often limited by the head required to raise the fluids to the collection point. Specifically, because the production rate of fluid typically declines with the head required to force the fluids from the well to the collection point, where a collection point is more distant or raised with respect to the well head, the production rate from the pumping system declines, in cases quite significantly. This is particularly problematic in wells that are located some distance from the collecting station, and in sub-sea wells from which production fluids must be raised to an elevated production vessel or a platform, or to a distant collection point.
There is a need, therefore, for an improved technique for producing fluids from production wells which provides both efficient production rates and which allows separation of wellbore fluid components. Moreover, there is a need for a technique which can be applied in a wide variety of environments, including with one or more land-based wells, with sub-sea wells, wells in environmentally sensitive areas, and the like.